In Loco Parentis
by acertainzest
Summary: Beckett finds out that her dad is dating again. Setting: mid- to late season 5. Just a silly bit of fluff for #CastleThemeDay; the theme this time is "family."


It was a slow day at the 12th Precinct, and as the morning dragged on toward noon, Kate Beckett sighed, "Well, at least it's almost lunchtime. Where do you want to go?"

"Oh," said Castle apologetically from his seat beside her desk, "I forgot to mention, I have to do this lunch meeting thing at the publishing office."

"Okay. No problem," Beckett shrugged. "Maybe I'll call my dad, see if he's free for lunch. Haven't seen him in a bit."

"Tell him I said hi." Castle looked at his watch. "Ooh, in fact, I should probably be going now. I'll see you back here later?" He glanced around the bullpen, hesitated briefly, then held out his hand. Beckett took it and shook, biting back a smile.

"See you later," she murmured, low, and watched him walk out. As he stepped into the elevator, Kate picked up her phone.

In moments, Jim Beckett's assistant came on the line. "Hi, Kate."

"Hi, Danielle. Is my dad around? I thought we could get together for lunch."

"Oh, sorry," the young woman replied, "he actually already left for a lunch date with his new girlfriend."

"His ... what?!" Beckett exclaimed, feeling her eyebrows shoot upward.

"Um." The voice on the line sounded distinctly embarrassed. "I'm so sorry. I just assumed that you knew. He's been having lunch with her almost every day for the last week or so."

"Oh," Kate said weakly. "Um. Well. Uh. I'll try again tomorrow?" She hung up, her face flaming.

* * *

"Come on, it's not that big a deal," Castle said a few hours later in the break room. "He's a grown man; he's entitled to some fun in life."

"I know that," Kate grumbled defensively, stirring sugar into her coffee with more vigor than strictly necessary.

"I mean, has he even been with anyone since your mom...?"

"Not that I know of," she admitted. "And, okay, I know I'm being unreasonable. It's not that I don't want him to be happy, to have a social life." She paused, and shuddered lightly. "I just don't want to know about it. Or think about it. Or have anything to do with it."

"Understandable," Castle nodded. "And that's probably why he hadn't told you about it."

Kate groaned. "I suppose you're right." A sudden realization hit her like an icy snowball to the back of the neck. "Oh my god," she breathed. "This is probably how Alexis feels about us." She winced deeply. "Oh god. I owe Alexis the biggest apology ever."

"I don't know if that would be a good idea," Castle grinned. She swatted his shoulder, scowling.

"Stop looking so gleeful. It isn't funny."

"It's a little funny," he protested, but he took the hint and dropped the subject.

* * *

That evening, Castle and Beckett were just walking up to the door of his loft when it flew open and Alexis emerged at a high rate of speed.

"Oh! Hi Dad, Beckett." She closed the door behind her and gave them a warning look. "Um. Gram has, uh, _company._ "

"Oh?" Castle's eyes widened. "Ohh."

"Yeah," his daughter agreed, grimacing, "and it got kinda loud, so, uh, I'll come back for my laundry some other time."

Castle and Beckett exchanged a look. "We'll go out to dinner," they decided in unison.

"Oh, but I really wanted to change my shoes," Beckett added, chewing her lower lip. "I left my flats in your bedroom." She winced and gave Alexis an apologetic look - she had vowed to stop talking bedroom stuff in front of her boyfriend's daughter - but the girl was scrolling on her phone and didn't seem to have noticed.

"You can get them later," Castle suggested, but Beckett shook her head.

"No, I need to change. These new heels are really pinching." She squared her shoulders determinedly. "I'll just dash in and grab them and come right back. You can wait here."

"Okay," he said, "but whatever you see or hear, I do _not_ want to know about it."

"What happened to _not that big a deal, entitled to some fun in life_?" Beckett teased, and he frowned at her.

"That only applies to other people's parents, Beckett, obviously."

"Oh, obviously," she rolled her eyes, and put her hand on the doorknob. "Okay, I'm going in. Wish me luck."

"Luck," Alexis stage-whispered, and Castle gave an encouraging thumbs-up.

Beckett opened the door and tiptoed across the living room and into Castle's bedroom. Finding the shoes she wanted, she quickly slipped off the uncomfortable heels and pushed her feet into the flats. She was halfway back toward the loft's exit when her boyfriend's mother appeared at the top of the stairs, calling back over her shoulder.

"Well, come along then, darling, a quick cup of coffee will perk us right up," Martha was saying, and Kate briefly froze, then tried to make a dash for it, but stopped in her tracks again when Martha spotted her from halfway down the stairs.

"Katherine?" The diva put a hand to her throat, apparently lost for words.

"Martha, um..."

"Coffee sounds great," came a male voice from above, and then the owner of the voice came into view, wearing one of Martha's gaudy silk bathrobes.

Beckett blinked, and blinked again, and then her scream reverberated loudly enough to bring Castle and Alexis barreling through the door in alarm.

"DAD?!"

"Oh ... Katie," Jim said sheepishly from the stairs, standing behind an unusually red-faced Martha.

"Mother!" gasped Castle.

"Oh my god," breathed Alexis, rooted to the spot.

A long moment of shocked silence ensued.

Jim Beckett was the one to break it. "Um, I'll just be upstairs," he announced, not meeting anyone's eyes, and retreated hastily.

"Castle, we're going," Kate announced, grabbing Castle's hand and tugging him toward the door. "We are going to find a restaurant and get very, very drunk and hope it kills the right brain cells."

"But-"

" _Now._ "

They exited, leaving Alexis and her grandmother staring at each other for another moment. At last, by mutual unspoken agreement, both redheads turned on their heels and departed. The loft was still and silent again for quite a while.

* * *

 _Author's Note: This story was inspired by episode 7x16 "The Wrong Stuff." In the episode, we see Martha coming down the stairs with a man in pajamas. When I first saw that episode, I was new to the show and hadn't learned all the characters yet, so I thought the guy with Martha was Beckett's dad. So when I heard that this week's #CastleThemeDay theme was family, this scene came immediately to mind._


End file.
